Compositions with enhanced capacity to absorb infrared (“IR”) radiation are desired in many applications, such as for solar control films for architectural and automobile glass, reheat additives in polymers, and additives to increase the drying and/or cure rate of polymeric coating compositions, among others. As a result, IR absorbing materials, such as indium tin oxide, antimony tin oxide, titanium nitride, and lanthanum hexaboride particles are often included in such compositions. For many applications, however, such particles do not provide a sufficiently high level of IR radiation absorption in the wavelength range of ˜800 to 1400 nanometers, which is often of particular commercial importance. As a result, to achieve adequate performance, the IR absorbing particles must often be included in the composition in amounts such they impart an undesired color to the composition in applications where colorless compositions are required. Moreover, since such additives are often relatively expensive, the cost impact of utilizing such additives in the required amount can often be prohibitive.
It would be desirable to provide optically clear IR radiation absorbing compositions comprising infrared absorbing particles dispersed in a binder in which the composition is transparent and colorless and exhibits excellent IR absorption in the wavelength range of ˜800 to 1400 nanometers.